A thrombus (blood clot) forming in a blood vessel is often an aggregation of blood elements such as platlets, fibrin and cellular elements. When an artery becomes blocked by a thrombus it leads to ischemic necrosis of the starved tissue, and when it occurs in an artery serving a critical organ, like for example, the heart or the brain, it may lead to severe injury or death.
The objective of the present invention is to provide a method for quickly removing a thrombus and a simple system to do so. The thrombectomy catheter system is insertable into blood vessels, preferably over a flexible guide-wire (guidewire insertion into a vessel is a common standard procedure) and it is made of a flexible catheter and a flexible piston, slidable therein. To operate, the distal end of the system is brought to the immediate vicinity of the thrombus and then the piston is quickly withdraw into the catheter, creating instantaneous pressure drop at its distal tip. The suddeness of the drop in pressure at the distal tip of the system helps to dislodge and suck the thrombus into the system for subsequent withdrawal out of the artery. In contrast, when a physician tries to suck a thrombus into a catheter by applying suction to the catheter's proximal end, the corresponding pressure dorp at the distal end appears dampened, and any flow through the catheter causes a substantial losses along the catheter, reducing the further the negative pressure at catheter's distal end.
The system's elements are shaped so that they are not likely to injure the vessel, especially since the system has to be brought to the vicinity of the thrombus but does not have to be forced across it. The above and other advantages of the invention will become apparent from the following discussion and the accompanying drawings.